There is known a system of scanning and spectroscopically measuring a measuring object, to early diagnose a skin disease such as a melanoma. A spectroscopic measuring apparatus has a spectroscope (first optical device) and an autofocus controller (second optical device) and arranges a slit mirror in the vicinity of a focus of an objective optical system. Reflected light from the slit mirror is detected with a position sensor, to autofocus-control the objective optical system. Transmitted light straight from the slit is made incident to the spectroscope and is spectroscopically measured with a diffraction grating. Scanning the measuring object provides two-dimensional spectroscopic information about the measuring object. With the use of part of the reflected light from the slit mirror, it is possible to monitor, with a two-dimensional camera, the measuring object other than the spectroscopically measured field. Related arts are, for example, Japanese Unexamined Patent Application Publications No. 2001-289619, No. 2001-208979, No. 2004-145372, and No. 2007-086470.